In a longitudinal study, patients with various kinds of central nervous system pathology will be given behavioral tasks that will provide quantitative descriptions of recovery at different points in time and will portray the changing patterns of defect. Our sampling of behavior will include not only cognitive, sensory, and motor capacities, but will also focus on objective measures of motivation and affect. Until now, the interaction of these two distinct classes of behavior during the course of recovery from an insult to the brain has been a relatively neglected topic. In this context, we plan to test the generality of the hypothesis that lesions incurred early in life are functionally less severe than lesions incurred later on. We shall also search for variations in task strategy that might be used to accelerate rates of recovery after brain insult and reduce the extent of lasting deficits. The results obtained in our laboratory will have obvious practical applications for better prognosis and management of infants, children, and adults with brain lesions due to a variety of causes.